Name and state the action and reaction in the following cases —

(a) firing a bullet from a gun,

(b) hammering a nail,

(c) a book lying on a table,

(d) a moving rocket,

(e) a person walking on the floor,

(f) a moving train colliding with a stationary train.

(a) Firing a bullet from a gun — When a man fires a bullet from a gun, a force F is exerted on the bullet (action) and the gun experiences an equal recoil R (reaction).

(b) Hammering a nail — When we hammer a nail, the hammer exerts a force F (action) on the nail and the nail in turn also exerts an equal and opposite force R (reaction) on the hammer.

(c) A book lying on a table — When a book is placed on a table top, the book exerts a force equal to it's weight (action) on the table in downward direction and the table balances it by an equal force called the (reaction) acting upwards on the book.

(d) A moving rocket — The rocket exerts a force F (action) on gases (produced by burning of fuel) to expel them through a nozzle backwards. The outgoing gases exert an equal and opposite force R (reaction) on the rocket due to which it moves in the forward direction.

(e) A person walking on the floor — When a man applies a force F (action) backward by his foot on the ground against the force of friction, the ground exerts an equal and opposite force R (reaction) forward on his foot.

(f) A moving train colliding with a stationary train — The moving train exerts a force F (action) on the stationary train and the stationary train in turn exerts a force R (reaction) on the moving train.